1. Field of the Invention
The present invention is directed primarily to truck bodies designed specifically for refuse hauling trucks and, more particularly, to an improved ejection mechanism for rear-loading refuse compactors which adds a significant amount of useful stowage capacity to the truck body.
2. Description of the Related Art
Refuse pick-up trucks commonly include a truck chassis fitted with a distinctly configured body that is completely designed and built and installed on the chassis by a manufacturer other than the manufacturer of the chassis. The truck body is, then, specifically designed for receiving, compacting, hauling and discharging refuse materials and includes all the associated operating mechanisms. One very successful design of refuse hauling truck bodies is known as a "rear loader" and includes a refuse hauling reservoir accessible for loading and discharge from the rear of the vehicle. This system includes an hydraulic compacting mechanism which repeatedly compacts the refuse after each loading. In this manner refuse eventually fills the available or useable reservoir volume extending from the front end back toward the rear of the body until no more material can be compacted.
The forward wall against which the refuse is compacted in a typical rear-loading truck body also forms part of a cylinder-operated ejection mechanism which, in effect, moves the front wall aft on an horizontal plane, in the manner of a plow, to expel the entire contents of the refuse volume during ejection. Typically, the bottom portion of the ejection mechanism is supported on a plurality of load-bearing sliders adapted to slidably support the ejector system just above the truck body floor. In many such truck models, the bottom portion of the truck body is provided with a central recessed trough extending beneath the central portion of the ejector in the form of a central longitudinal ejection cylinder trough running the length of the body. An hydraulic cylinder which mounts behind the cab on the truck chassis is designed to mount in and to operate along the trough and move the ejector system fore and aft in the refuse collecting body. A portion of the ejector system extends down into the central longitudinal trough and is fitted with a plate which is, in turn, fastened to the end of the operating piston of the hydraulic cylinder.
The cylinder is operated to position the ejector system as desired. When the cylinder is fully retracted, the ejector is in the fully forward position as when the truck is fully loaded with refuse. When the cylinder is fully extended the ejector mechanism is moved fully aft of the truck body to a position where the refuse will be completely expelled.
It will be appreciated that the length of the cylinder requires that, even in its fully retracted position, a distance up to one-third the length of the fully extended cylinder and piston is required between the rear of the cab and the point at which the cylinder engages the ejection mechanism. This means that even in the fully contracted configuration, the cylinder takes up considerable space along the central longitudinal trough. In order to accommodate the operating cylinder beneath the ejector mechanism, the design of the ejector mechanisms has had to be such that the bottom portion of the ejector mechanism extend a considerable distance into the useful reservoir or volume of the truck. This has led to conventional body designs in which the ejector mechanism vertically follows the front wall of the available reservoir space for a short distance below the top of the truck body but then is thereafter required to angle sharply toward the rear of the truck body, away from the front wall. While it solves the problem of ejector operation, it renders a rather large wedge-shaped volume in the lower front portion of the refuse reservoir unusable. In a large truck, this unused space may amount to several cubic yards and considerably reduces the effective volume of a given sized rear-loading refuse compactor body.
If the wasted space associated with the conventional ejection mechanism could be reduced or eliminated, it would present a distinct step forward in the art of rear-loading, compacting refuse truck body design. This would result, of course, in more efficient use of the possible reservoir volume for the purposes intended.